When I ran my company, I used Quick Books. After one of the updates, you had to use their tax table update service (at $6/mo) to do payroll. How often to do you suppose there is actually a change by the Fed or a state tables? If at all, at most once a year. The following year Intuit doubled the rate and I canceled that service. Then, they refused to print the 941, W-2 and W-3 forms even though you manually updated the appropriate accounts.

Fsck 'em, I say!